A 1st U.S. Circuit Court of Appeals panel on March 14 ordered U.S. District Court Richard G. Stearns to recuse himself from the case, finding that his prior employment as head of the U.S. Attorney's Criminal Division in Boston and his close friendship with FBI Director Robert Mueller created an appearance of impropriety.In the ground-breaking decision, retired U.S. Supreme Court Justice David H. Souter said the case should be reassigned to a new judge "whose curriculum vitae does not implicate the same level of institutional responsibility" as Stearns'.

Though Casper was a federal prosecutor from 1999 to 2004 and served for a time as deputy chief of the Organized Crime Drug Enforcement Task Force, there has been no suggestion that she called any of the shots in the Bulger saga or played nearly as active a role as Stearns.

A review of the Bulger docket, however, reveals that an appearance-of-impropriety argument potentially could be raised over Casper's continued involvement in the case.

Less than four months before Casper was randomly selected to take over U.S. v. Bulger, defense attorneys J.W. Carney Jr. and Hank Brennan filed a motion in her courtroom seeking access to sealed documents in the case of Peter Limone. They argued in a Nov. 7 filing that they needed the Limone documents because they were relevant to several contested issues in Bulger.

Rather than rule on the motion, as other judges dealing with similar requests had done, Casper quickly stepped aside. On the same day that Carney and Brennan made their request, Casper responded with the following one-sentence answer: "I hereby recuse myself from consideration of the above-entitled case pursuant to 28 U.S.C., section 455."

That statute states that a judge shall disqualify herself from any proceeding in which her impartiality might reasonably be questioned. It also requires recusal if a judge has a personal bias in the matter, has served as a lawyer in the case, or has a financial interest in it.

While a judge is not obligated to specify the reason for recusal, it's not a stretch to suggest that Casper's lack of explanation could cause reasonable members of the public to wonder what prompted her to step aside.

Was it because she felt that her prior work in the U.S. Attorney's Office required her to do so?

Was it because Limone was prosecuted for extortion and gambling crimes by Middlesex County prosecutors during a time that she served as the office's deputy district attorney?

Or was it something else?

The answer is no one knows.

As Souter wrote in his recusal opinion, public perception is key in this unprecedented case that promises to further expose the unseemly relationship between federal law enforcement and organized crime.

With unanswered questions swirling over Casper's reason for recusing herself in November, it's certainly plausible that a member of the public watching the proceedings could reasonably conclude something doesn't smell right.

If the name of the game in Bulger is to ensure that the trial is conducted in a completely above-board manner, wouldn't it make sense to have a judge in place who did not feel the need, just a few months ago, to step away from the case?